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Biomedical subjects

N Trivedi

Publications and source records attributed to N Trivedi.

52 records · Page 3Linked to original sources
PubMed1991

Effects of clear liquids on gastric volume and pH in healthy volunteers.

The effects of clear liquids on gastric volume and pH were examined in 30 healthy ASA physical status I volunteers. After overnight fasting, a Salem-sump nasogastric tube was inserted and gastric contents were removed for measurement of volume and pH. Gastric contents were then reinserted through the nasogastric tube into the stomach. The volunteers were randomly divided into three groups: group 1 (n = 10) received 240 mL water, group 2 (n = 10) received 240 mL coffee, and group 3 (n = 10) received 240 mL pulp-free orange juice. All liquids were administered orally. Gastric contents were then again aspirated, measured for volume and pH, and reinserted through the nasogastric tube every half hour until gastric volume was less than 25 mL. All volunteers had gastric volumes less than 25 mL with a slight decrease in pH within 2 h of orally taking one of the three 240-mL liquids. These data suggest that if patients have ingested a moderate amount of clear liquids it is safe to conduct general anesthesia after a 2-h fast in healthy surgical patients.

Administration, Oral↗
PubMed1988

Hypofractionated external radiation with high and low dose rates in the treatment of advanced cancer of the cervix.

Thirteen patients with cancer of the cervix Stage IIIb (heavy) were treated with high (9) and low (4) dose rates, once a week. A total dose of 4200 cGy was delivered over 7 weeks with a fraction size of 600 cGy. Six of nine patients showed complete response following high dose rate hypofractionated radiation. It is felt that synchronization of cells into a sensitive phase during low dose rate radiation is not the determinant of outcome even when duration of treatment is only 5 to 6 hours.

Female↗
PubMedDate not supplied

Improved vascularization of planar membrane diffusion devices following continuous infusion of vascular endothelial growth factor.

Improving blood vessel formation around an immunobarrier device should improve the survival of the encapsulated tissue. In the present study we investigated the formation of new blood vessels around a planar membrane diffusion device (the Baxter Theracyte System) undergoing a continuous infusion of vascular endothelial growth factor through the membranes and into the surrounding tissue. Each device (20 microl) had both an inner immunoisolation membrane and an outer vascularizing membrane. Human recombinant vascular endothelial growth factor-165 was infused at 100 ng/day (low dose: n = 6) and 500 ng/day (high dose: n = 7) for 10 days into devices implanted s.c. in Sprague-Dawley rats; noninfused devices transplanted for an identical period were used as controls (n = 5). Two days following the termination of VEGF infusion, devices were loaded with 20 microl of Lispro insulin (1 U/kg) and the kinetics of insulin release from the lumen of the device was assessed. Devices were then explanted and the number of blood vessels (capillary and noncapillary) was quantified using morphometry. High-dose vascular endothelial growth factor infusion resulted in two- to threefold more blood vessels around the device than that obtained with the noninfused devices and devices infused with low-dose vascular endothelial growth factor. This increase in the number of blood vessels was accompanied by a modest increase in insulin diffusion from the device in the high-dose vascular endothelial growth factor infusion group. We conclude that vascular endothelial growth factor can be used to improve blood vessel formation adjacent to planar membrane diffusion devices.

Animals↗
PubMedDate not supplied

Differentiation and expansion of beta cell mass in porcine neonatal pancreatic cell clusters transplanted into nude mice.

Neonatal porcine pancreas has considerable capacity for growth and differentiation, making it an attractive potential source of islet tissue for xenotransplantation. Pancreases from 1-3-day-old newborn pigs were digested with collagenase and cultured for 8 days. The resulting cellular aggregates are called porcine neonatal pancreatic cell clusters (NPCCs). The mean yield of NPCCs from a newborn pig was 28,200 +/- 1700 islet equivalents. Cytokeratin 7 (CK7) was used as a marker for the immunostaining of pancreatic duct cells. In neonatal pancreas, 18% of the insulin-positive cells co-stained for CK7, thus being protodifferentiated. NPCCs also contained protodifferentiated cells; insulin/PP and insulin/somatostatin co-stained cells were more common than insulin/glucagon cells. Between 1 and 8 days of culture, the DNA content of the NPCCs fell to 16% and the insulin content to 33% of the starting value, mainly due to the preferential loss of exocrine cells. Transplantation of 2000 or 4000 NPCCs into diabetic nude mice typically normalized glucose values in 10-20 weeks. Mice with successful grafts had lower fasting blood glucose levels than normal mice and accelerated glucose clearance after an i.p. glucose load. The starting NPCCs consisted of 17% insulin-staining cells, but the grafts of mice with reversed diabetes consisted of 94% beta cells, with some co-stained for CK7, indicating that the grafts still contained immature cells. The mass of insulin-producing cells rose from 0.22 +/- 0.08 mg 1 week after transplantation to 4.34 +/- 0.27 mg in mice sacrificed at 27-35 weeks. In summary, NPCCs contain mostly islet precursor cells, which when transplanted into nude mice undergo striking differentiation and beta cell expansion.

Animals↗